Regulation of transcription translation

Question 1

How does transcription begin

Answer 1

The gene is switched on by specific molecules that move from cytoplasm to the nucleus. (TRANSCRIPTIONAL FACTORS).
When the TF binds it causes this region of DNA to begin transcription.

Question 2

How does the transcriptional factor bind to DNA?

Answer 2

Has a site that binds to a specific base sequence of DNA nucleotides.

Question 3

What happens when a gene is not being expressed?

Answer 3

The site the TF binds to is not active

Question 4

What does a non active TF binding site cause?

Answer 4

Unable to start transcription and polypeptide synthesis.

Question 5

How do hormones affect transcription?

Answer 5

1. can switch on a gene
2. by combining with receptor site on TF
3. this activates DNA binding site by causing it to change shape

Question 6

Properties of oestrogen that make it able to start transcription?

Answer 6

1. lipid-soluble molecule, can diffuse through phospholipid bilayer
2. Complementary shape to receptor molecule on TF

Question 7

How does Oestrogen affect transcription PT.1?

Answer 7

1. lipid soluble so diffuses through C.S.M. into cell
2. Oestrogen binds to complementary shaped receptor molecule on TF
3. Causes DNA binding site to change shape so its complementary to DNA and can now bind.

Question 8

How does Oestrogen affect transcription PT.2?

Answer 8

4. Transcriptional factor can now enter nucleus through nuclear pore and bind to specific base sequences on DNA.
5. The combination of the transcriptional factor with DNA stimulates the transcription of the gene.